<template>
	<view>
		<view class="scroll-view-container">
			<!-- 左侧滚动 -->
			<scroll-view scroll-y class="left-scroll-view" :style="{ height: `${wh}px` }">
				<block v-for="(item, i) in cateList" :key="i">
					<view class="scroll-view-item" :class="{ active: i === active }" @click="handleActiveChange(i)">{{ item.cat_name }}</view>
				</block>
			</scroll-view>

			<!-- 右侧区域 -->
			<scroll-view scroll-y class="right-scroll-view" :style="{ height: `${wh}px` }" :scroll-top="scrollTop">
				<view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
					<view class="cate-lv2-title">/ {{ item2.cat_name }} /</view>
					<!-- 三级分类数据列表 -->
					<view class="cate-lv3-list">
						<view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
							<image :src="item3.cat_icon"></image>
							<text>{{ item3.cat_name }}</text>
						</view>
					</view>
				</view>
			</scroll-view>
		</view>
	</view>
</template>

<script>
import { getCateListData } from '../../api/cate.js';

export default {
	data() {
		return {
			cateList: [],
			// 二级分类
			cateLevel2: [],
			// 当前选中索引
			active: 0,
			// 当前设备可用高度
			wh: 0,
			// 当前右侧滚动距顶部的距离
			scrollTop: 0
		};
	},
	onLoad() {
		const sysInfo = uni.getSystemInfoSync();
		console.log(sysInfo);
		this.wh = sysInfo.windowHeight;

		this.getCateList();
	},
	methods: {
		handleActiveChange(i) {
			this.active = i;

			// 设置右侧滚动
			this.scrollTop = this.scrollTop ? 0 : 1;
			// 重新渲染二级分类
			this.cateLevel2 = this.cateList[i].children;
		},
		gotoGoodsList(item3) {
			uni.navigateTo({
				url: `/subpkg/goods_list/goods_list?cid=${item3.cat_id}`
			})
		},
		async getCateList() {
			const { data: res } = await getCateListData();
			if (res.meta.status !== 200) return uni.$showMsg();
			this.cateList = res.message;

			// 得到二级分类
			this.cateLevel2 = res.message[0].children;
		}
	}
};
</script>

<style lang="scss">
.scroll-view-container {
	display: flex;

	.left-scroll-view {
		width: 120px;

		.scroll-view-item {
			font-style: 12px;
			line-height: 60px;
			text-align: center;
			background-color: #f7f7f7;

			&.active {
				position: relative;
				background-color: #fff;

				&:before {
					position: absolute;
					left: 0;
					top: 50%;
					transform: translateY(-50%);
					display: block;
					content: '';
					width: 3px;
					height: 30px;
					background-color: #c00;
				}
			}
		}
	}

	.right-scroll-view {
		.cate-lv2 {
			.cate-lv2-title {
				padding: 15px 0;
				font-size: 12px;
				font-weight: 700;
				text-align: center;
			}

			.cate-lv3-list {
				display: flex;
				flex-wrap: wrap;

				.cate-lv3-item {
					display: flex;
					flex-direction: column;
					align-items: center;
					width: 33.33%;

					image {
						width: 60px;
						height: 60px;
					}
					text {
						padding: 5px 0 10px;
						font-size: 12px;
					}
				}
			}
		}
	}
}
</style>
